Control vane arrangement for a gas turbine engine

ABSTRACT

A control vane arrangement for a turbine has an even number of vanes in a duct or chamber surrounding the turbine rotor. Alternate vanes are movable in either direction from positions in which they are transverse to the direction of fluid flow, and the remaining vanes are movable in either direction from positions in which they are substantially aligned with the direction of gas flow. All the vanes move simultaneously and when one set of vanes is transverse the other set is substantially aligned. Fluid flow to the turbine rotor can be controlled so as to reverse the direction of rotation of the turbine, fluid flow being effectively shut off before the rotor direction is reversed.

[111 3,816,021 June 11, 1974 1 CONTROL VANE ARRANGEMENT FOR A 3,588,270 6/1971 Boeles..................... 3,719,427 3/1973 FOREIGN PATENTS OR APPLICATIONS GAS TURBINE ENGINE [75] Inventors: Geoffrey Arthur Lewis, Solihull;

Joseph Louis Bloom, Droitwich, both of England [73] Assignee: Lucas Aerospace Limited,

380,701 9/1932 Great Britain...................... 415/163 911,839 5/1954 Germany 415/152 Primary Examiner-Henry F. Raduazo Bummgham, England Attorney, Agent, or Firm-Holman & Stern Dec. 11, 1972 [22] Filed:

ABSTRACT A control vane arrangement for a turbine has an even number of vanes in a duct or chamber surrounding the turbine rotor. Alternate vanes are movable in either direction from positions in which they are transverse w a D .m r o i r P n .m WM 8. W A

Dec. 11, 1971 Great Britain.................... 57663/71 to the direction of fluid flow, and the remaining vanes [52] US. 415/147,415/152,415/163 are movable in either direction from Positions in which they are substantially aligned with the direction of gas flow. All the vanes move simultaneousl [51] lnt. F0ld l/30 y and when one set of vanes is transverse the other set is substantially aligned. Fluid flow to the turbine rotor i1 0 m ,7 m3 1 ,2 95 41 l 7 19 75 4.1 l 1 5 H6 1 4 m6 "H m5 .1 4 c -l m m d l .w F N 5 [56] Refer Cit d can be controlled so as to reverse the direction of ro- UNITED STATES PATENTS tation of the turbine, fluid flow being effectively shut off before the rotor direction is reversed.

2,854,211 9/1958 Bendersky 415/160 3,025,036 3/1962 Kumm et a1 415/160 10 Claims, 6 Drawing Flgures PATENTEDJUN 1 1 I974 3816LO21 sum 1 or 3 I PATENTEnJuu 1 1 1914 3.8161321 SHEETEUF 3 FIGA.

CONTROL VANE ARRANGEMENT FOR A GAS TURBINE ENGINE BACKGROUND OF THE INVENTION This invention relates to a control vane arrangement for a turbine.

SUMMARY OF THE INVENTION According to the invention a control vane arrangement for a turbine comprises a first chamber surrounding the turbine rotor, a second chamber communicating with an inlet for the turbine, an even number of vanes pivotally mounted between the first and second chambers, past which vanes a fluid flows, in use, from the inlet to the rotor, means for pivotally moving alternate vanes in either direction from positions in which they are transverse to the direction of fluid flow, and means for pivotally moving the others of said vanes in either direction from positions in which they are substantially aligned with the directing gas flow, i.e., the leading and trailing edges lie on common circles, angular movement of said alternate vanes in one direction being accompanied by a larger angular movement of said other vanes in the opposite direction, and the arrangement being such that when'said alternate vanes are in said substantially aligned positions, said other vanes are in said transverse positions.

BRIEF DESCRIPTION OF THE DRAWING Examples of the invention will now be described with reference to theaccompanying drawings in which:

FIG. 1 shows diagrammatically a control vane arrangement,

FIGS. 2 to 4 show, to an enlarged scale, different operating positions of three adjacent vanes of FIG. 1,

FIG. 5 shows a view, corresponding to FIG. 2, of an alternative embodiment of the invention, and

FIG. 6 shows a similar view of yet another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION Referring first to FIGS. 1 to 4, a gas turbine engine 10 is arranged to supply a part of its compressor output to a separate work turbine 11. Surrounding blades 12 of the work turbine 11 is a duct or chamber 13 which communicates with the outlet of the compressor of the engine 10 and through which gas flows to the turbine 11. Pivotally mounted in the duct 12 are an even number of vanes 14. Coupled to alternate ones 14a of vanes 14 are pinions l5. Coupled to the remaining ones 14b of vanes 14 are pinions 16 having a smaller pitch circle diameter than pinions 15. The ratio of the pitch circle diameters is such that a 40 rotation of pinions 15 results in a 140 rotation of pinions 16. Each of the pinions 16 meshes with the pinions 15 on either side. Surrounding the pinions 15 and engaging the pinions 15 is a ring gear 17. The ring gear is rotatable between a first position in which the vanes 14 are in the positions shown in sector B of FIG. 1 and in FIG. 2, and a second position in which the vanes 14 are in the positions shown in sector C of FIG. 1 and in FIG. 4. The pinions 15, 16 are interengaged so that there is an intermediate position of the vanes 14, as shown in sector A of FIG. 1 and in FIG. 3, in which vanes 14a are substantial aligned with the direction of gas flow and vanes 14b are transverse to the direction of gas flow. In this intermediate position gas flow to the work turbine is effectively shut off.

In use, therefore, the vanes 14 are movable from the intermediate positions shown in FIG. 3 to the positions shown in FIG. 2, in which latter position the work turbine is rotated anticlockwise, as seen in FIG. 1. During this movement the amount of gas flow to the work turbine is progressively increased. Similarly the vanes 14 are movable in the opposite directions from the positions shown in FIG. 3 to those shown in FIG. 4, to cause the work turbine to rotate in a clockwise direction, gas

' flow to the work turbine being progressively increased,

as before. The vane arrangement thus causes gas flow to be reduced to its minimum before a reverse impulse is applied to the work turbine.

In the alternative arrangement shown in FIG. 5 the vanes 14b have associated drive pins 23 radially spaced from the pivotal axis of vanes 14b. Associated with the vanes 14a are slotted drive members 18 which engage the pins 23. Each of the pins 23 is movable about its associated vane axis by an associated arm 19, with the arms 19 being interconnected by links 20. The operation of this alternative arrangement is substantially the same as that described with reference to FIG. 1, vanes 14b rotating through a larger angle than vanes 14a and gas flow to the work turbine being effective shut off before reversal of thrust.

The further alternative shown in FIG. 6 has vanes 14a 14b independently operable by corresponding link arrangements 21, 22. In a modified form of this alternative arrangement, the link arrangement 22 coacts with the vanes 14b at a lesser radius from the pivotal axes thereof than the distance of the link arrangement 21 from the axes of vanes 14a. This modification is indicated at 22a and enables link arrangements 21, 22a to be operated by a single actuator.

We claim:

1. A control vane arrangement for a radial flow turbine having a rotor and an inlet, comprising a first chamber surrounding the turbine rotor, a second chamber communicating with the turbine inlet, an even number of vanes pivotally mounted between the first and second chambers, past which vanes a fluid flows, in use, from the inlet to the rotor, means for pivotally moving alternate vanes in either direction from positions in which they are transverse to the direction of fluid flow, and means for pivotally moving the others of said vanes from positions in which they are substantially aligned with the direction of gas flow, angular movement of said alternate vanes in one direction being accompanied by a larger angular movement of said other vanes in the opposite direction, and the arrangement being such that when the leading and trailing edges of said alternate vanes substantially lie on common circles, said other vane are in said transverse position thereof.

2. The arrangement as claimed in claim 1 in which the means for pivotally moving said alternate ones of the vanes comprises first toothed gear elements secured to said alternate ones, and the means for pivotally moving said others of the vanes comprises second toothed gear elements secured to said others of the vanes, each first gear element meshing with a second gear element being less than that of said second gear elements 3. The arrangement as claimed in claim 2 in which each first gear element meshes with two of said second gear elements, and each second gear element meshes with two of said first gear elements.

4. The arrangement as claimed in claim 2 which includes a third gear element meshing with said selected ones of said gear elements and rotatable between a first position in which said vanes are inclined in one direction from a radial position with respect to the turbine axis, and a second position in which said vanes are inclined in the opposite direction from said radial position.

5. The arrangement as claimed in claim 4 in which said third gear element is a ring gear which meshes with said second gear elements.

6. The arrangement as claimed in claim in which the means for pivotally moving said alternate vanes comprises arms respectively secured to said alternate vanes for pivotal movement therewith, and links interconnecting said arms at positions thereon remote from the pivotal axes of said alternate vanes. v

7. The arrangement as claimed in claim 6 in which the means for pivotally moving said other vanes comprises abutments respectively associated with said alternate vanes and spaced from the pivotal axes thereof by distances which are less than the spacing from said pivotal axes of the positions on said arms interconnected by said links, and drive members secured to said other vanes and engaging said abutments.

8. The arrangement as claimed in claim 6 in which the means for pivotally moving said other vanes comprises further arms respectively secured to said other vanes for pivotal movement therewith, and links interconnecting said arms at positions thereon remote from the pivotal axes of said other vanes.

9. The arrangement as claimed in claim 8 in which the links interconnecting said further arms engage the latter at positions thereon which are spaced from the pivotal axes of said other vanes by a less amount than the spacing from the pivotal axes of said alternate vanes of the links interconnecting the first mentioned arms.

10. The control vane arrangement as claimed in claim 1, in which said alternate vanes are movable from positions in which they are substantially radial with respect to the turbine rotor axis, and said other vanes are movable from positions in which they are substantially tangential to the turbine rotor. 

1. A control vane arrangement for a radial flow turbine having a rotor and an inlet, comprising a first chamber surrounding the turbine rotor, a second chamber communicating with the turbine inlet, an even number of vanes pivotally mounted between the first and second chambers, past which vanes a fluid flows, in use, from the inlet to the rotor, means for pivotally moving alternate vanes in either direction from positions in which they are transverse to the direction of fluid flow, and means for pivotally moving the others of said vanes from positions in which they are substantially aligned with the direction of gas flow, angular movement of said alternate vanes in one direction being accompanied by a larger angular movement of said other vanes in the opposite direction, and the arrangement being such that when the leading and trailing edges of said alternate vanes substantially lie on common circles, said other vane are in said transverse position thereof.
 2. The arrangement as claimed in claim 1 in which the means for pivotally moving said alternate ones of the vanes comprises first toothed gear elements secured to said alternate ones, and the means for pivotally moving said others of the vanes comprises second toothed gear elements secured to said others of the vanes, each first gear element meshing with a second gear element being less than that of said second gear elements
 3. The arrangement as claimed in claim 2 in which each first gear element meshes with two of said second gear elements, and each second gear element meshes with two of said first gear elements.
 4. The arrangemeNt as claimed in claim 2 which includes a third gear element meshing with said selected ones of said gear elements and rotatable between a first position in which said vanes are inclined in one direction from a radial position with respect to the turbine axis, and a second position in which said vanes are inclined in the opposite direction from said radial position.
 5. The arrangement as claimed in claim 4 in which said third gear element is a ring gear which meshes with said second gear elements.
 6. The arrangement as claimed in claim 10 in which the means for pivotally moving said alternate vanes comprises arms respectively secured to said alternate vanes for pivotal movement therewith, and links interconnecting said arms at positions thereon remote from the pivotal axes of said alternate vanes.
 7. The arrangement as claimed in claim 6 in which the means for pivotally moving said other vanes comprises abutments respectively associated with said alternate vanes and spaced from the pivotal axes thereof by distances which are less than the spacing from said pivotal axes of the positions on said arms interconnected by said links, and drive members secured to said other vanes and engaging said abutments.
 8. The arrangement as claimed in claim 6 in which the means for pivotally moving said other vanes comprises further arms respectively secured to said other vanes for pivotal movement therewith, and links interconnecting said arms at positions thereon remote from the pivotal axes of said other vanes.
 9. The arrangement as claimed in claim 8 in which the links interconnecting said further arms engage the latter at positions thereon which are spaced from the pivotal axes of said other vanes by a less amount than the spacing from the pivotal axes of said alternate vanes of the links interconnecting the first mentioned arms.
 10. The control vane arrangement as claimed in claim 1, in which said alternate vanes are movable from positions in which they are substantially radial with respect to the turbine rotor axis, and said other vanes are movable from positions in which they are substantially tangential to the turbine rotor. 